Conventional optical data storage (CD's / DVD's) store data in two dimensions, recording reflective marks on a storage medium (a disk). These disks could potentially hold multiple layers of recording medium to increase storage capacity, but an issue arises in that as you go multiple layers deep, layers closer to the reading mechanism (a laser,) interfere with the reading process and create noise. 3D storage methods circumvent this problem by using multi-planar storage methods to allow the laser to address only the specified unit of data storage. This allows for an immense amount of potential storage – theoretically, petabytes of data could be stored using this method. Additionally, this method of storage is not limited to disks – one could potentially store data in 3D objects, like spheres or cubes. The main requirement for 3D storage is that the medium can undergo chemical changes when exposed to light in order to allow writing and reading; if these changes can be reversed, unlimited rewriting of the data is possible.
Unfortunately, development of 3D storage has been slow due to lack of serious financial backing. Though the field appears lucrative, the capital required to get to a level of development where the method would be financially self-supporting is viewed as cost-ineffective. Though there are companies investing in this technology, development continues to move slowly. Some companies have made claims in the past that they would have marketable 3D solutions by 2010, though they have failed to make good on their claims. Perhaps the future will see more focused research done on 3D storage as people seek greater amounts of storage space. Only time will tell.